Prestressed hollowcore concrete plank leveler device

ABSTRACT

A device for leveling or aligning adjacent prestressed hollowcore concrete planks includes an insert member that is received between the planks at a grout joint. One end of the insert member supports a first alignment member that is received against one side of the planks. The other end of the insert member cooperates with a second alignment member that is received against an opposite side of the planks. An adjustment member adjusts the spacing between the first and second alignment members to provide a desired alignment between the planks.

BACKGROUND OF THE INVENTION

[0001] This invention generally relates to a device for aligning orleveling adjacent prestressed hollowcore concrete planks.

[0002] Prestressed hollowcore concrete planks have been used for manyyears in constructing various types of structures such as apartmentbuildings, schools, motels, etc. A variety of challenges are presentedto those assembling such structures. One particular challenge is toproperly align or level adjacent planks. This is particularly importantat the interface between the planks to achieve a consistent elevation orsurface profile across an entire level.

[0003] Prestressed hollowcore concrete planks are well known. Each plankincludes a plurality of prestressed cables running the length of theplank. A plurality of cavities or openings run parallel to theprestressed cables. The nature of the concrete material and the presenceof the prestressed cables creates the possibility for there to be cambervariations in different planks. The amount of camber in a planktypically depends on the size of the plank, the length of the plank andthe amount of exposure to natural elements during storage. This presentsa problem when assembling structures because varying amounts of camberin the planks causes variations in the floor elevation on the top of theplanks and corresponding variations in the ceiling surface of the lowerside of the planks. It is necessary to bring adjacent planks intoalignment to assure a consistent profile along the surfaces of theplanks. This problem is particularly apparent in situations where planksof different lengths are necessary to accommodate a building design.Longer planks tend to have larger amounts of camber than smaller planks.

[0004] One attempt at compensating for variations in plank camber hasbeen to use an elongated bolt that is positioned between adjacentplanks. In a conventional arrangement metal plates typically are placedagainst the planks and nuts are placed on the opposite ends of the bolt.Adjusting the positions of the nuts assists in drawing the planks intoalignment with each other.

[0005] One drawback associated with the elongated bolt technique is thatthe spacing between the planks must be set wide enough to accommodatethe bolt. This introduces variations along the surface provided by theplanks because adjacent planks that do not need camber adjustment have avery small gap (on the order of one-quarter of an inch) while adjacentplanks that require adjustment have a much wider gap (on the order ofone inch). Such variations in the gap size between adjacent planks doesnot provide a consistent surface appearance, which is undesirable.

[0006] Another drawback associated with the elongated bolt technique isthat a worker typically needs to climb a ladder at the position of eachbolt in order to be able to secure the nut on the end of the bolt thatextends down from a lower side of one of the levels of planks. Thisintroduces additional labor, safety concerns and expense into a job.

[0007] There is a need for a plank leveler device that facilitates moreeconomically aligning adjacent planks to accommodate variations incamber. Additionally, there is a need for a device that permits moreconsistent spacing between adjacent planks so that a better overallsurface profile is achieved. This invention meets those needs whileavoiding the shortcomings and drawbacks of prior devices.

SUMMARY OF THE INVENTION

[0008] In general terms, this invention is a device for aligningadjacent prestressed hollowcore concrete planks. A novel insert memberis configured to readily fit between adjacent planks. A first alignmentmember is supported by the insert member and is adapted to be receivedagainst a first side of the planks. A second alignment member issupported by the insert member and adapted to be received against asecond side of the planks. A jacking member allows a worker to adjust aspacing between the first and second alignment members such that thesurfaces of the adjacent planks are drawn into alignment with eachother.

[0009] In one example, the insert member includes a threaded portion onone end that extends beyond the planks and an opposite end that includesat least one opening. One of the alignment members is received withinthe opening on one side of the planks while the other alignment memberis received over the threaded portion. By adjusting a nut over thethreaded portion, the spacing between the alignment members is adjustedand the planks are drawn into a desired position.

[0010] This invention is particularly well suited for use in aligningadjacent prestressed hollowcore concrete planks. The various featuresand advantages of this invention will become apparent to those skilledin the art from the following detailed description of the currentlypreferred embodiment. The drawings that accompany the detaileddescription can be briefly described as follows.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011]FIG. 1 diagrammatically illustrates a device designed according tothis invention.

[0012]FIG. 2 is a front view of an insert member designed according tothis invention.

[0013]FIG. 3 is a side view of the insert member of FIG. 2.

[0014]FIG. 4 illustrates an example alignment member designed accordingto this invention.

[0015]FIG. 5 illustrates another example alignment member designedaccording to this invention.

[0016]FIG. 6 illustrates an alternative insert member.

[0017]FIG. 7 illustrates another alignment member, which is intended tobe used with the example of FIG. 6.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] A system 20 includes a device 22 for aligning adjacentprestressed hollowcore concrete planks 24 and 26. The planks includetensioned cables 28 and openings 29 that extend the length of the planksas known in the art. An insert member 30 is positioned between the twoplanks preferably by inserting one end 32 through the grout jointbetween the planks 24 and 26. The first end 32 preferably includes atleast one receiver portion. The illustrated example of FIGS. 1-3includes three openings 34, 36 and 38, each of which is adapted toreceive an alignment member 40. Multiple openings are shown in theillustrated embodiment to accommodate different plank thicknesses.

[0019] A significant advantage provided by this invention is that theinsert member 30 allows for consistent spacing between adjacent planksregardless of whether camber adjustment is necessary. The insert memberpreferably has a thickness t that is small enough to permit tightspacing between adjacent planks so that the spacing is consistent acrossan entire surface. The preferred arrangement includes a thickness on theorder of approximately ¼ inch. In one example, the thickness t is{fraction (5/16)} inch.

[0020] The insert member 30 preferably also includes a width w that isapproximately eight times as great as the thickness t. In one example,the width w is two inches. The larger width permits the thickness t tobe small enough to accommodate tight spacing between adjacent plankswhile still providing enough strength in the insert member to withstandthe forces necessary for jacking the adjacent planks into alignment.

[0021] The insert member 30 preferably is made from a steel material.The preferred embodiment includes a high strength leaf spring steel. Onesuch steel is sold under the trade name Viking 100 High Strength Steelby Nelson Steel Company.

[0022] A first alignment member 40 preferably is received within one ofthe receiver portions 34, 36 or 38. The example first alignment member40 of FIGS. 1 and 4 is made from a piece of reinforcing bar that is bentinto a generally L-shape configuration. One edge 42 of the barpreferably is ground flat and adapted to be received against one side ofthe concrete planks 24 and 26. In one example, the length of the surface42 on the alignment member 40 is approximately six inches.

[0023] In the illustrated example, the first alignment member 40 isreceived against the underside (according to the drawings) of the planks24 and 26. One portion 44 of the alignment member 40 preferably extendsaway from the planks so that a worker 45 can use a handle 46 to maneuverthe alignment member 40 into position as needed. The alignment member 40preferably is centered relative to the insert member 30 and the planks24 and 26 for accuracy and stability.

[0024] The insert member 30 preferably includes a threaded end 50opposite from the end 32. The illustrated example includes a threadedrod that preferably is welded at 52 onto the insert member 30. In oneexample, the insert member includes a punched hole in a body portion ofthe insert member 30 into which a corresponding portion of the threadedmember is received prior to being welded in place.

[0025] Another example insert member is formed from a single stamping.In this example, the body of the insert member and the threaded rodportion are formed as one piece and no welding is necessary.

[0026] The illustrated example includes a tapered portion 54 on thethreaded rod 50 that preferably tapers down to a thickness consistentwith the body portion of the insert member 30 (i.e., approximately ¼inch).

[0027] A second alignment member 60 is a generally flat metal plate inthe illustrated example. A jacking member or nut 62 preferably isthreaded onto the threaded end 50 after the plate 60, which includes ahole 64, is received over the threaded end of the rod 50. The spacingbetween the first alignment member 40 and the second alignment member 60can be readily adjusted by turning the nut 62 about the threaded portionof the rod 50. The shape of the insert member prevents the insert memberfrom spinning while adjusting the nut 62. Adjusting the spacing betweenthe alignment members jacks the planks 24 and 26 into an alignedposition as needed and secures them in place.

[0028] A preferred way of using the illustrated example includespositioning the plate 60 and nut 62 onto the threaded end 50. The insertmember 30 is then inserted into the grout joint between the planks 24and 26. The worker 45 then slides the second alignment member 40 intoone of the receiver openings in the end 32 of the insert member 30. Thejacking member 62 is then adjusted until the planks 24 and 26 arealigned as desired. It is preferred to utilize the adjustment of thejacking member 62 to bring the planks as close as possible into a leveland aligned position without over-tightening or causing damage to theplanks. Then, the planks are ready for a conventional application ofconcrete grout. It is preferred to leave the leveling device 22 inposition for at least two days after the grout is applied beforeremoving the leveling device. Those with experience in the field willrealize how many devices 22 are required along an interface betweenplanks to achieve a desired result.

[0029] The device 22 may be used to assist in aligning the planks byadjusting the spacing between the alignment members. Alternatively, thedevice 22 may be used to maintain an alignment of the planks that isestablished independent of the device 22.

[0030]FIG. 6 illustrates an alternative embodiment of an insert member70. In this example, a plurality of notches 72, 74 and 76 are formed inone end 78 of the insert member body. The main difference between theexample of FIG. 6 and that of FIGS. 2 and 3 is the nature of thereceiving portions. In the example of FIG. 6, a plurality of notches areused while in the example of FIGS. 2 and 3 a plurality of openingsthrough the insert member are used.

[0031] A modified alignment member 80 is illustrated in FIG. 7. Thisexample includes a generally flat portion having arms 82 and 84extending in the same direction parallel to each other. A spacingbetween the arms 82 and 84 is set so that the alignment member 80 isslidably received onto the insert member 70. Specifically, the armportions 82 and 84 are received within a chosen set of notches on theend 78 of the insert member 70.

[0032] A dowel portion 86 preferably extends away from one side of thebody of the alignment member 80 so that the handle 46 is useful forselectively positioning the alignment member 80 into the receiverportions on the insert member 70.

[0033] The example of FIG. 7 includes reinforcing portions 88 thatextend generally perpendicularly from the body portion of the alignmentmember 80. Having the reinforcing portions provides greater stiffness tothe alignment member 80, which is beneficial for maintaining a desiredalignment between adjacent planks without deforming the alignment member80.

[0034] One advantage to an alignment member as illustrated in FIG. 7compared to the one illustrated in FIGS. 1 and 5 is that the contactsurface area between the alignment member and the surface of theconcrete planks is increased. Greater surface area contact betterdistributes the forces associated with jacking the adjacent planks intoa desired alignment. This lessens the possibility for causing anycracking or other damage to the planks in the area where adjustment isbeing made.

[0035] This invention provides an efficient and economical arrangementfor aligning and leveling adjacent prestressed hollowcore concreteplanks. The description provided here is exemplary rather than limitingin nature. Variations and modifications to the disclosed examples maybecome apparent to those skilled in the art that do not necessarilydepart from the essence of this invention. The scope of legal protectiongiven to this invention can only be determined by studying the followingclaims.

I claim:
 1. A device for aligning adjacent prestressed hollowcoreconcrete planks, comprising: an insert member that is adapted to bereceived between the concrete planks, the insert member having athickness and a width that is greater than the thickness; a firstalignment member supported by the insert member that is adapted to bereceived against a first side of the planks; a second alignment membersupported by the insert member that is adapted to be received against asecond side of the planks; and a jacking member that adjusts a spacingbetween the first and second alignment members such that the planks aredrawn into a desired alignment.
 2. The device of claim 1, wherein theinsert member includes a threaded portion and the jacking membercomprises a nut that is received on the threaded portion and rotated toadjust the spacing between the alignment members.
 3. The device of claim1, wherein the first alignment member is slidably received at leastpartially within a corresponding receiver portion on the insert member.4. The device of claim 3, including a plurality of receiver portions onthe insert member.
 5. The device of claim 4, wherein the receiverportions each comprise an opening through the insert member.
 6. Thedevice of claim 3, wherein the first alignment member comprises a rodhaving at least one generally flat surface portion that is adapted to bereceived against the concrete planks.
 7. The device of claim 6,including a handle that is selectively received over a portion of therod to slide the rod into a selected position relative to the receiverportion of the insert member and the planks.
 8. The device of claim 1,wherein the second alignment member comprises a steel plate.
 9. Thedevice of claim 8, wherein the insert member includes a threaded endthat is received through an opening in the steel plate and theadjustment member comprises a nut that is received over the threadedend, the nut being rotated to adjust the spacing between the alignmentmembers.
 10. The device of claim 1, wherein the insert member comprisesa generally flat plate having a length that is greater than a thicknessof the concrete planks, the plate having at least one opening at one endfor at least partially receiving the first alignment member and athreaded portion at an opposite end that cooperates with the adjustmentmember.
 11. The device of claim 10, wherein the threaded portion isrounded at a distal end and tapered on two sides into a configurationthat corresponds to a thickness of the generally flat plate.
 12. Thedevice of claim 1, wherein the insert member thickness is about ⅛ thewidth.
 13. The device of claim 12, wherein the thickness isapproximately ¼ inch and the width is approximately 2 inches.
 14. Thedevice of claim 1, wherein the insert member includes at least one setof notches and the second alignment member includes arm portions thatare received at least partially within the notches.
 15. A method ofaligning adjacent concrete planks comprising the steps of: inserting aninsert member between the two planks at the interface of the planks;positioning a first alignment member near one end of the insert membersuch that the first alignment member is positioned against one side ofthe planks; sliding a second alignment member in a direction that isgenerally perpendicular to the insert member until the second alignmentmember is supported on the insert member and the second alignment memberis positioned near an opposite side of the planks; and adjusting aspacing between the alignment members to provide a desired alignment ofthe planks.
 16. A device for aligning adjacent concrete planks,comprising: a first member that is adapted to be inserted betweenadjacent concrete planks; a second member that cooperates with the firstmember and is received against one side of the planks; a third memberthat is slidably received at least partially within a receiver portionon the first member and that cooperates with the first member and isreceived against a second side of the planks; and an adjuster thatadjusts a position of the third member relative to the second member toprovide a desired alignment between the planks.
 17. The device of claim16, wherein the first member has a thickness and a width that is muchgreater than the thickness.
 18. The device of claim 17, wherein thewidth is approximately eight times greater than the thickness.
 19. Thedevice of claim 16, wherein the third member comprises a rod having afirst segment that is adapted to be received against the planks and asecond segment that extends generally perpendicular from the firstsegment.
 20. The device of claim 16, wherein the third member includes agenerally flat body portion and a dowel extension that extends generallyperpendicularly away from the flat body portion.